The law in Texas regarding child support is pretty settled. It is set up to make it as much as a mechanical 'calculator' as possible. There are multiple tables, graphs and other strict rules for calculating support.
For example, a parent who does not have any other children will usually have to pay 20% of their net income as child support - if they don't have custody of their child. They will also have to insure the child on reasonably health insurance.
By agreement of the parties, this can be modified. However, there is little for the primary parent to do so, since they know they will 'win' in Court on the child support calculation issue.
If you would like to CALCULATE THE AMOUNT OF YOUR CHILD SUPPORT OBLIGATION, SIMPLY CLICK HERE TO BE RE-DIRECTED TO THE TEXAS ATTORNEY GENERAL'S OFFICIAL CHILD SUPPORT CALCULATOR.